Study: three subtypes of depression
The exact causes of depression are still unclear, although around 300 million people worldwide suffer from mental illness. The Japanese research team has taken a step closer to deciphering this puzzle. The researchers were able to decompose depression into three different forms. In one of these forms, the drugs have no effect.
The team of neural computing at the Institute of Science of Okinawa has established three types of depression that are fundamentally different. According to researchers, the three different subtypes largely depend on two factors. On the one hand, functional patterns of connections between brain regions and, on the other hand, traumatic child experiences are defined. In one of three forms, total antidepressants do not show any effect. The results of the study were recently published in the scientific journal "Scientific Reports".
Depression can have different bases
Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed drugs for depression affecting many patients. However, these drugs do not work the same way in all people and in some people, depression does not improve when taken. "It has always been thought that there are different types of depression and that affect the effectiveness of the drug," says Professor Kenji Doya in a press release on the study's results.
Course of the study
In their study, researchers studied the brain of participants. In total, brain activity patterns in 78 different regions of the brain were analyzed by magnetic resonance. In addition, blood was searched and people had to fill out the questionnaires and asked for sleep habits, stress problems and other mental illnesses.
How are the forms of depression different?
Three different forms of depression have emerged from the study. "This is the first study to identify subtypes of life-history depression and MRI data," explains Doya. There are types of depression at once:
- Type D1: This type of depression is characterized by a high functional brain function. Especially related areas are, in particular, brain regions that are responsible for the processing of speech and numbers, spatial perception and attention. In addition, the history of childhood trauma is also affected.
- Type D2: This subtype is characterized by a high functional brain function, but there are no traumatic experiences in childhood.
- Type D3: In this form, it was possible to detect only a small functional connection of the brain, and the affected persons did not have any traumatic experiences in childhood.
In whom depression medication does not show any effect
According to the research group, a group of patients who had childhood injuries and greater connectivity of the brain region (type D1) had depressive suppression. SSRIs were ineffective. In contrast, the other two groups generally respond positively to treatment, according to Japanese scientists.
New treatment techniques are needed
According to researchers, the study shows that new techniques of treatment need to be explored and put into place. Especially for those with depression D1 new therapies should be created. "Our study gives promising directions for scientists who are studying neurobiological aspects of depression to continue their research," concluded Professor Doya. (Vb)